Known identification systems image a container to determine whether explosives, drugs, weapons, and/or other contraband are present within the container. Some of the known systems are configured to determine whether a thin object is present within the container. At least one known method for detecting objects in computed tomography (CT) data, including sheet-shaped objects such as sheet explosives, includes analyzing a neighborhood of voxels surrounding a test voxel and eroding the data by identifying a neighborhood of voxels surrounding a voxel of interest. In such a method, if the number of voxels having densities below a predetermined threshold exceeds a predetermined number, then it is assumed that the test voxel is a surface voxel and is removed from the object. The known method also includes applying a connectivity process to voxels to combine them into objects after sheets are detected to prevent sheets from being inadvertently removed from the data by erosion. Then a dilation function can then be performed on the eroded object to replace surface voxels removed by erosion. However, such known methods may generate false alarms because random pixels are connected and are then identified as a thin object, when no thin object exists.
Other known identification methods use density and/or atomic number to identify components of an object, but are not specifically directed to identifying a thin object.